Intraoral dental radiology positioning device for use with aiming ring

ABSTRACT

A receptor positioning device for taking dental bitewing radiographs of a patient&#39;s teeth comprises a receptor holding member adapted to receive a receptor for exposing x-radiation from the x-ray machine and a collimation plate having a substantially flat surface for aligning with an x-ray machine. The collimation plate has a rectangular opening in its surface for passage of radiation from the x-ray machine to expose a receptor in the receptor holding member and a pair of handles extending away from the plate for positioning the device. The collimation plate is constructed of metal having a thickness of at least 0.075 in., preferably at least 0.100 in., to reduce the passage of radiation from the x-ray machine to the patient except at the plate opening. The device also includes an arm between the collimation plate and the receptor holding member, the arm including a biting surface for engaging the patient&#39;s teeth to secure the device in the patient&#39;s mouth, and an aiming ring secured to the arm at a position distal from the receptor holding member, with the collimation plate being secured to the aiming ring. The aiming ring may also include notches and the collimation plate preferably includes clips for removably securing the plate to the aiming ring and tabs for locating the plate relative to the aiming ring notches.

This application is related to an application by the same inventor filed on even date herewith as Ser. No. 10/899,249 entitled “Intraoral Dental Radiology Positioning Device.”

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to devices for dental radiographic procedures or intraoral diagnostics, and more particularly, to intraoral dental radiology positioning devices relating to positioning x-ray film or receptors in a patient's mouth during radiographic procedures.

2. Description of Related Art

Intraoral x-ray diagnosis involves positioning an x-ray film within a patient's mouth next to the inner surface of the teeth or bone being studied. The film is then exposed to an x-ray beam generated outside the mouth and passing through the target. Known intraoral dental radiography typically employs a dental device having an alignment member including an x-ray film holding structure at one end, an aligning arm at another end, and a bite plate positioned between the ends. The alignment member (also known as an aiming ring) may include a collimation structure for collimation of an x-ray beam to conform more accurately to the size and shape of the x-ray film held by the film holding structure. A commonly prescribed dental radiograph is the “bitewing”, whereby an image is acquired of the crowns of the teeth biting together and their surrounding socket bone. Also typical is film mounted in a holder which includes a bite block portion extending from the film in the direction of the external x-ray tube. The patient bites down on the bite block with the target teeth and holds the film in position next to the target.

Many dental radiographic techniques utilize beams of circular cross-section despite the fact that the dental films are typically rectangular in shape. A disadvantage of known devices is that the cross-sectional area of the beam used by the radiographic technique is typically larger than the surface area of the x-ray film. When the cross-sectional area of the beam does not match the film size, the patient can be exposed to unnecessary radiation which irradiates tissues beyond the borders of the dental film. Typical film positioning instruments may also allow unwanted x-radiation to pass through the film holding instrument.

Another disadvantage of current x-ray film positioning instruments is that there can be errors in aiming the x-ray. These errors are frequently associated with a rectangular position-indicating device attached to an x-ray machine. Also, there can be errors in orientation of the long axis of the substantially rectangular typical position indicating devices with the long axis of the film in the patient's mouth. Aiming and orientation errors expose the patient to needless retakes of radiographs.

Typical film positioning devices and instruments include multiple parts, requiring assembly and adjustment. The multiple arrangements of parts may lose their set position which can cause a reduction in the sharpness of the acquired image.

Enhancing the ability to sterilize dental equipment is desirable in the field. Current film positioning devices may have disadvantages when sterilizing because parts, such as cushioned areas, may be less accessible or receptive to steam, heat or chemical methods. Difficulty in disinfecting or sterilizing is associated with a rectangular positioning indicating device attached to an x-ray machine

Another disadvantage of current x-ray film positioning instruments is that the patient can only bite on the bite plate to assist in positioning and holding a film positioning device in the mouth. Typical devices may be difficult to grasp and manipulate in the patient's mouth making it problematic for the patient to assist in positioning the instrument.

Bearing in mind the problems and deficiencies of the prior art, it is therefore an object of the present invention to provide a device which will reduce patient exposure of x-radiation.

It is a further object of the present invention to provide a device which will reduce aiming error and cone cuts.

It is another object of the invention to provide a device which will improve the quality of the acquired image on the receptor-x-ray film.

It is yet another object of the present invention to provide a device which will universally adapt to traditional film and electronic/digital receptors, and also to typical film holding instrument aiming rings.

It is a further object of the present invention to provide a device which will minimize movement of the interconnected parts of the device once the parts are desirably positioned.

It is another object of the present invention to provide a device which minimizes movement of the device in the patient's mouth.

It is yet another object of the present invention to provide a device which precisely sets the x-ray source to align with the receptor, or film.

It is a further object of the present invention to provide a device which limits magnification and keeps magnification uniform.

It is another object of the present invention to provide a device which maximizes sharpness of the acquired image on the film.

It is a further object of the present invention to provide a device which facilitates sterilization.

It is another object of the present invention to provide a device which is of maximum durability.

It is yet another object of the present invention to provide a device which minimizes patient discomfort and malpositioning.

It is a further object of the present invention to provide a device which minimizes “retakes” of radiographs.

It is another object of the present invention to provide a method of positioning a film-positioning device in a patient's mouth providing an unobstructed line between an x-ray device and x-ray film.

It is another object of the present invention to provide a device which can rotate the orientation of the central rectangular opening of a collimator.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.

SUMMARY OF THE INVENTION

The above and other objects, which will be apparent to those skilled in art, are achieved in the present invention which is directed to, in a first aspect, a receptor positioning device for taking dental bitewing radiographs of a patient's teeth, which comprises a receptor holding member adapted to receive a receptor for exposing x-radiation from the x-ray machine and a collimation plate having a substantially flat surface for aligning with an x-ray machine. The collimation plate has an opening in its surface, preferably rectangular, for passage of radiation from the x-ray machine to expose a receptor in the receptor holding member and a handle extending away from the plate for positioning the device. The collimation plate is constructed of metal having a thickness of at least 0.075 in., preferably at least 0.100 in., to reduce the passage of radiation from the x-ray machine to the patient except at the plate opening. The device also includes an arm between the collimation plate and the receptor holding member, the arm including a biting surface for engaging the patient's teeth to secure the device in the patient's mouth.

In a related aspect, the present invention is directed to a method for taking dental bitewing radiographs of a patient's teeth comprising providing a receptor positioning device of the type described above, and providing a receptor on the receptor holding member. The method then includes positioning the receptor holding member in the patient's mouth and the patient's teeth on the biting surface to secure the device in the patient's mouth, adjusting the position of receptor positioning device by grasping the handle extending from the collimation plate, aligning an x-ray machine with the substantially flat surface of the collimation plate, and passing radiation from the x-ray machine through the opening of the collimation plate while substantially blocking passage of radiation through the collimation plate thickness to expose the receptor.

The device includes an aiming ring secured to the arm at a position distal from the receptor holding member, and the method includes securing the collimation plate to the aiming ring. The aiming ring may include notches and the collimation plate preferably includes clips for removably securing the plate to the aiming ring and tabs for locating the plate relative to the aiming ring notches. The method then includes bending the clips to secure the collimation plate to the aiming ring and inserting the collimation plate tabs into the aiming ring notches.

The device preferably includes a pair of handles extending from the collimation plate, which handles may be opposite each other or at approximately a right angle to each other. The method then includes grasping the handles to adjust the position of receptor positioning device.

In another aspect, the present invention is directed to a receptor positioning device for taking dental bitewing radiographs of a patient's teeth comprising a collimation plate defining a substantially central opening. A receptor holding member is adapted to receive a receptor, and an elongated arm including a biting surface is positioned toward a distal end thereof. The elongated arm is adapted to receive and couple at a first end to the collimation plate. The elongated arm is designed and adapted to extend towards and couple to a rear portion of the receptor holding member, opposite the collimation plate, such that an unobstructed path is defined between the substantially central opening of the collimation plate and the receptor received by the receptor holding member. The receptor holding member may preferably accommodate a plurality of receptor dimensions, films, and digital receptors. In a preferred embodiment of the present invention, the collimation plate, the receptor holding member, and the elongated arm are rigidly fixed together. In another preferred embodiment of the present invention, the collimation plate, the receptor back plate, and the elongated arm are constructed of metal.

In a related aspect, the present invention is directed to a receptor positioning device for taking dental bitewing radiographs of a patient's teeth, which comprises a collimation plate having an opening therein for aligning an x-ray machine and a receptor holding member adapted to receive a receptor for exposing x-radiation from the x-ray machine. An elongated arm is coupled at a first end to the collimation plate and includes a biting surface positioned toward a distal end thereof. The elongated arm from the biting portion distal end further extends towards the collimation plate and is coupled to the receptor holding member, such that an unobstructed path is defined between the substantially central opening of the collimation plate and the receptor received by the receptor holding member while the patient's teeth engage the biting portion distal end.

The biting portion distal end on the elongated arm, adjacent the receptor back plate, may include an incompressible receiving portion adapted for biting with the patient's teeth. Optionally, the biting portion distal end includes an elastomeric impression material adapted for creating and registering with an occlusion pattern of the patient's teeth. Openings in the biting portion distal end permit the elastomeric impression material to couple to the distal end surface.

The collimation plate may include handles opposite of one another for the patient to grasp. The opening in the collimation plate is preferably substantially rectangular in shape, is orientated similarly to the film having a substantially rectangular shape, and the substantially central opening defined by the collimation plate is adapted to correspond dimensionally to the dimensions of the receptor. Preferably, the collimation plate is constructed of metal having a thickness of at least 0.075 in. to prevent overexposing the patient to needless additional radiation.

In another related aspect, the biting surface is adjacent to the receptor holding member such that the receptor is positioned behind the patient's teeth. The receptor holding member may include notches in an edge for receiving at least one band to secure together the receptor and holding member. Where the receptor is a digital receptor having a data cord, there may be further included a connector securing the data cord to the elongated arm between the collimation plate and the receptor holding member.

In another aspect of the present invention, a receptor positioning device for taking dental bitewing radiographs of teeth inside a patient's mouth, comprises a rigid, fixed structure including a collimation plate defining a substantially rectangular opening, a receptor holding member adapted to receive a receptor, and an elongated arm being adapted to receive and couple at a first end to the collimation plate. The elongated arm is designed and adapted to extend towards and couple at a second end to a rear portion of the receptor holding member, opposite the collimation plate, such that an unobstructed path is defined between the substantially rectangular opening of the collimation plate and the receptor received by the receptor holding member. A biting surface is fixedly attached to a distal end of the elongated arm and adjacent to the receptor holding member such that the receptor is positioned behind the teeth on which the radiographs being taken while the biting surface is gripped by teeth on the opposite side of the patient's mouth.

In yet another aspect of the present invention, a method for taking dental bitewing radiographs of a patients' teeth comprises initially providing a receptor positioning device of the type describe above. Preferably, the device is a rigid, fixed structure including a collimation plate defining a substantially central opening, a receptor holding member adapted to receive a receptor, and an elongated arm being adapted to receive and couple at a first end to the collimation plate. The elongated arm is designed and adapted to extend towards and couple to a rear portion of the receptor holding member such that an unobstructed path is defined between the substantially rectangular opening of the collimation plate and the receptor received by the receptor holding member. A biting surface is provided which is fixedly attached to a distal end of the elongated arm and adjacent to the receptor holding member such that the receptor is positioned behind the patient's teeth on which the radiographs is being taken while the biting surface is gripped by teeth on the opposite side of the patient's mouth. The patient's teeth bite on the biting surface such that an unobstructed x-ray path is defined between the collimation plate and the receptor received by the receptor holding member. An x-ray machine is aligned with the opening of the collimation plate, and the receptor is exposed such that x-radiation from the x-ray machine passes along the unobstructed path defined between the collimation plate and the receptor.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the invention believed to be novel and the elements characteristic of the invention are set forth with particularity in the appended claims. The figures are for illustration purposes only and are not drawn to scale. The invention itself, however, both as to organization and method of operation, may best be understood by reference to the detailed description which follows taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of the receptor positioning device of the present invention.

FIG. 2 is a front elevational view of the collimation plate of the device shown in FIG. 1.

FIG. 3 is a side elevational view of the receptor positioning device shown in FIG. 1 depicting the position of the patient's teeth.

FIG. 4 is another side view of the receptor positioning device shown in FIG. 1 rotated 180° from the view in FIG. 3.

FIG. 5 is a side elevational view of the elongated arm of the receptor positioning device shown in FIG. 1.

FIG. 6 is a side view of the elongated arm of FIG. 5.

FIG. 7 is a side elevational view of another embodiment of an elongated arm of the receptor positioning device shown in FIG. 1

FIG. 8 is a side view of the elongated arm of FIG. 7.

FIG. 9 is a front elevational view of another collimation plate for use with the receptor positioning device shown in FIG. 1 having a rectangular hole of different dimensions.

FIG. 10 is a front elevational view of another collimation plate for use with the receptor positioning device shown in FIG. 1 having a rectangular hole of still different dimensions.

FIG. 11 is a side view of the receptor positioning device shown in FIG. 1 depicting the patient's teeth biting the device and the x-ray machine in position.

FIG. 12 is a back plate for receiving receptor of the receptor positioning device shown in FIG. 1.

FIG. 13 is a side elevational view of the back plate of FIG. 12.

FIG. 14 is another embodiment of a back plate for receiving electronic receptors of the receptor positioning device shown in FIG. 1, having opposing notches.

FIG. 15 is a side elevational view of the back plate of FIG. 14.

FIG. 16 is a perspective view of the receptor positioning device of the present invention incorporating a digital receptor.

FIG. 17 is a perspective view of an embodiment of the collimation/shield device of the present invention, with attachment member, intended for use with a typical prior art film holding instrument.

FIG. 18 is a rear elevational view of the shield device shown in FIG. 17.

FIG. 19 is a front elevational view of the attachment member shown in FIG. 17.

FIG. 20 is a side elevational view of the shield device shown in FIG. 17.

FIG. 21 is a top view of the shield device shown in FIG. 17.

FIG. 22 is a top view of the attachment member shown in FIG. 19.

FIG. 23 is a side elevational view of the attachment member shown in FIG. 19.

FIG. 24 is a side elevational view of the clip for the attachment member shown in FIG. 19.

FIG. 25 is a front elevational view of a typical prior art aiming ring with which the present invention is useful.

FIG. 26 is a cross-sectional view of the aiming ring of FIG. 25, along line 26—26, showing the insertion of the corner locator tabs of the shield device of FIG. 17 into the index indentations of the aiming ring.

FIG. 27 is a cross-sectional view of the aiming ring of FIG. 25, along line 27—27, showing the clip attachment of the shield device of FIG. 17.

FIG. 28 is a top plan view of the shield device of FIG. 17 attached to a typical intraoral film holding instrument positioned in the patient's mouth, with the x-ray machine in position.

FIG. 29 is a side elevational view of the shield device shown in FIG. 17 attached to a typical intraoral film holding instrument positioned in the patient's mouth, with the x-ray machine in position.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

In describing the preferred embodiment of the present invention, reference will be made herein to FIGS. 1–29 of the drawings in which like numerals refer to like features of the invention. Features of the invention are not necessarily shown to scale in the drawings.

A preferred embodiment 10, shown in FIGS. 1–6 and 11, depicts the intraoral dental radiology receptor positioning device of the present invention. Referring to FIGS. 1–4, the receptor positioning device includes a substantially flat collimation plate 12, having a surface area 14. The surface area 14 defines a substantially central rectangular opening 16. The collimation plate 12 further includes opposing elongated handles 18 extending outward on opposite sides thereof. The receptor positioning instrument 10 further includes an elongated arm 20 and a film or electronic receptor holding member 28 having a back plate 30 and clips 32 for holding x ray film or electronic receptors. The elongated arm 20 is connected at a bent first end 40 to the back of the collimation plate 50, preferably, by welding or other rigid connection. The elongated arm further includes a second end 22 attached to the rear surface 52 of the back plate 30 of the receptor holding member 28, opposite collimator plate 12.

The film or electronic receptor holding member 28 back plate 30 is preferably of metal and the opposing clips 32 are designed and adapted to receive and grasp a removable film or digital-electronic receptor 54. The elongated arm 20 includes a flat upper surface 26 adapted to receive a patient's teeth. The patient's teeth 60 a on one side of the mouth are positioned to grip the substantially flat biting surface 26 of the elongated arm 20, as shown in FIG. 3. The biting surface receiving portion is normally incompressible. Optionally, biting surface 26 on arm 20, behind the receptor plate 54, includes a plurality of circular perforations or openings, for example the three 6 mm diameter openings 70 longitudinally spaced 8 mm apart as shown in FIG. 3. These openings accommodate a curable elastomeric impression material 72, on either side of biting surface 26 (see also FIGS. 4–6, which may be used to create and register with the unique occlusion pattern of the patient's teeth, as also shown in FIG. 11. This registration may be removed, archived and reused to create reproducible x-ray images of the teeth in repeated sequential exposures over time.

The film or receptor 54 held on the back plate 30 by the clips 32 of the receptor holding member 28 is positioned behind the desired teeth 60 b to be exposed, on the opposite side of the patient's mouth. Preferably, the back plate 30 and receptor 54 are parallel to collimation plate 12. The film or receptor 54 is thereby positioned to be exposed to an x-ray from the x-ray machine 62 to show the condition of teeth 60 b, as shown further in FIG. 11.

Referring to FIG. 2, the collimation plate 12 further includes a preferably rectangular opening 200 positioned substantially in the center of the collimation plate 12. The opening 16 has a vertical dimension 202, and a horizontal dimension 204. In the preferred embodiment shown in FIGS. 1 and 2, the vertical dimension 202 of the opening is about 1.210 in. (3.1 cm), and the horizontal dimension 204 is preferably about 1.552 in. (3.9 cm). The collimation plate 12 is adapted to axially align the x-ray machine's position indicating cylinder device 62 with the receptor 54, as shown by the x-ray centerline 63. It does this in two ways. First, the x-ray machine is easily centered because the two devices, 12, 62, have substantially the same diameter. Axial offset would be apparent by extension of the outer edge of collimation plate 12 beyond the outer rim of the x-ray machine position indicating cylinder device 62. Second, substantially full, flat contact of the collimation plate 12 with the x-ray machine's position indicating cylinder device 62, as shown in FIG. 3, would assure optimal alignment of the x-ray receptor with the x-ray beam.

The orientation and size of the rectangular collimation opening described above is for use with the adult size horizontal bitewing radiographic examination of patients with normal anatomy and dentitions. Other sizes may be made for small children or for other uses. While existing commercially available metal collimation plates generally have on the order of 0.050 in. (1.27 mm) thickness, the inventor's dosimetry studies have shown that this thickness still permits a substantial amount of radiation to penetrate and expose the patient to needless additional radiation. Preferably, the thickness T of the collimation plate (FIG. 4) has at least 0.075 in. (1.9 mm) thickness, more preferably 0.080 (2.0 mm) or 0.100 in. (2.5 mm) or more to block such excess radiation.

Referring to FIGS. 5 and 6, the substantially flat elongated arm 20 of the preferred embodiment shown in FIG. 1 is shown including the first end 40, the second end 22, a short member 23 (on which biting surface 26 is located) having a first length 25, and an angled portion 21. FIG. 5 shows arm 20 as a flat blank prior to forming at the dotted lines, while FIG. 6 shows arm 20 after forming, where both ends 22 and 40 are bent approximately 90° . The second end 22 of the elongated arm 20, and the outer edge of the angled portion 21 define a first dimension 27. The first dimension 27 is preferably about 1.25 in. (3.2 cm), and the first length 25 is preferably about 2.54 in. (6.45 cm). The outer edge of the short member 23 and the vertical plane define an angle 29 which determines the angulation of the short member 23 of the elongated arm 20. The preferred angle 29 is about 12° . These dimensions and angles are preferred for three reasons. First, the dimension of the elongated arm is consistent with optimal placement of an x-ray receptor in mouths with normal anatomy and dentitions ranging in size from that of a child (8 years and up) to very large. Second, the dimension of the elongated arm is compatible with accommodating conventional film and digital-electronic receptors currently available. Third, the dimension of the elongated arm is compatible with accommodating the x-rays machine's position indicating cylinder device in optimal configuration with the receptor in the patient's mouth.

Referring to FIGS. 7 and 8, another embodiment of an elongated arm 100 is shown which can be used with the receptor positioning device 10 shown in FIGS. 1–4. The elongated arm 100 includes the first end 40, the second end 22, the angled portion 21, and the short member 23 as in the embodiment shown in FIGS. 5 and 6. Again, FIG. 7 shows arm 20 as a flat blank prior to forming at the dotted lines, while FIG. 8 shows arm 20 after forming, where both ends 22 and 40 are bent approximately 90° . However, here the short member has a second length 106 which is more than the dimension 25 of the embodiment shown in FIGS. 1 and 5–6. The second length 106 is preferably about 2.85 in. (7.2 cm). The second end 22 of the elongated arm 20, and the outer edge of the angled portion 21 define a second dimension 104 which is less than the first dimension 27 of the embodiment shown in FIGS. 1 and 5–6. The second dimension 104 is less than the first dimension shown in FIG. 5 and preferably about 1.10 in. (2.8 cm). The outer edge of the short member 23 and the vertical plane define an angle 108 which is less than or more acute than the angle 29 of the embodiment shown in FIGS. 5 and 6 and is preferably about 7° . The more acute angle 108 better accommodates deep overbite occlusions. This other embodiment of the elongated arm has a dimension that is easily accommodated in mouths that have anatomy with deep overbites (retrognathic mandibles) ranging in size from that of a child to a large adult.

Referring to FIGS. 9–10, other embodiments of a collimation plate 12 are shown including opposing elongated handles 18. Referring to FIG. 9, the collimation plate 12 further includes a preferably rectangular opening 210 positioned substantially in the center of the collimation plate 12, where the length of the opening 210 is smaller than the width. The opening 210 has a vertical dimension 212, and a horizontal dimension 214. In this embodiment, the vertical dimension 212 of the opening is preferably about 1.552 in. (3.9 cm), and the horizontal dimension 214 is preferably about 1.210 in. (3.1 cm). This embodiment offers a different positioning of the opening to correspond to an adult receptor or film held in the receptor holding member 28. The orientation and size of the rectangular collimation opening is for use with the adult size vertical bitewing radiographic examination. This is useful for observing compromised dentitions (with large restorations and height of alveolar crest bone decreased by marginal periodontal disease) that would not be visualized on horizontal bitewing images.

Referring to FIG. 10, the collimation plate 12 further includes a preferably rectangular opening 220 positioned substantially in the center of the collimation plate 12. The opening 220 has a vertical dimension 222, and a horizontal dimension 224. In this embodiment the vertical dimension 222 of the opening is about 1.000 in. (2.5 cm), and the horizontal dimension 224 is preferably about 1.552 in. (3.9 cm). This embodiment is designed to correspond to a child's receptor or film held in the receptor holding member 28. The size and orientation of the rectangular collimation opening is for use for horizontal bitewing examinations in small children (4–8 years) and very small adults or adults with limited ability to open their mouths.

Referring to FIGS. 12 and 13, the back plate 30 is shown of the device of FIG. 1. FIG. 12 shows the flat blank for plate 30 and FIG. 13 shows plate 30 after forming. The back plate 30 includes the clips 32 and preferably has an overall length 36 of about 1.71 in. (4.3 cm), and a dimension between the clips 38 of preferably about 1.578 in. (4.0 cm), as they are shown formed and curled in FIG. 13. The preferred dimension 34 between the back plate 30 and the formed clip 32 is about 0.05 in. (1.3 mm). The overall length 36 of the back plate 30 with the clips 32 curled, as shown in FIG. 13, is preferably about 1.71 in. (4.3 cm), and the length 38 between the curled clips 32 is preferably about 1.578 in. (4.0 cm). The width 35 of the back plate 30 is preferably about 1.20 in. (3.05 cm). The dimensions herein accommodate standard intraoral dental film.

Referring to FIGS. 14 and 15, another embodiment is shown of the back plate 30. As before, FIG. 14 shows the flat blank for plate 30 and FIG. 15 shows plate 30 after forming. The embodiment shown in FIGS. 14 and 15 is the same as in the embodiment shown in FIGS. 12 and 13 except in the addition of two opposing notches 39. These notches are on opposite sides of the back plate and are on adjacent sides with reference to the clips 32. The notches 39 are a specified dimension 31 from the midpoint of the long side of the back plate 30. The dimension 31 is preferably about 0.15 in. (3.8 mm). The notches 39 accept electronic receptors to the back plate 30 of the receptor holding member 28 with the aid of orthodontic elastics (not shown). The overall length 36, the length 38 between the curled clips 32, and the width 35 of the back plate 30 is the same as in the previous embodiment shown in FIGS. 12–13. FIG. 16 shows receptor 54 held in place on receptor holding member 28 by a pair of orthodontic elastic bands 76 which are received in two spaced pairs of notches 39. Where the receptor 54 is a digital-electronic receptor, data cord 78 extending from the receptor may be secured to and along elongated arm 20 by connector 80, between the collimation plate and the receptor holding member, so that data plug 82 may be positioned outside the patient's mouth.

Other back plate sizes may be used, such as one designed for receptors or film used for children which is smaller than the films used with the back plates shown in FIGS. 12–15. Such a back plate would preferably have a length between the curled clips of about 1.60 in. (4.1 cm) long similar to the embodiments shown in FIGS. 12–15, but, a width of preferably about 1.00 in. (2.5 cm) wide to accommodate size film designed for children.

In operation and use, referring to FIG. 11, the patient's mouth 65 is outlined and the patient's teeth are above and below the elongated arm 20 of the receptor positioning device 10. Teeth 60 a bite down on and grip biting portion 26 of arm 20. Biting portion 26 may contain elastomeric impression material which conforms to the occlusion pattern of the patient's teeth 60 a. The receptor holding member 28 is positioned behind the teeth 60 b to be exposed (on the opposite side of the mouth from teeth 60 a) and the collimation plate 12 is positioned in adjacent to the patient's mouth 65 and teeth 60 b. The x-ray machine 62 is positioned to take an x-ray in front of the collimation plate 12 and expose the x-ray film receptor 54. If necessary, the patient or radiographer may use handles 18 to reposition the receptor positioning device for better comfort or aim. Preferably the collimation plate 12 is constructed of a metal and rigidly and fixedly fashioned. The rigid and fixed construction of the receptor positioning device 10 provides the most accurate film exposure because there is minimal opportunity for unwanted movement after positioning the device. The metal collimation plate having a rectangular opening 16 reduces patient exposure by absorbing approximately 50% of primary beam x-radiation for the most commonly prescribed dental radiograph, which is the bitewing. Further, the metal collimation plate reduces aiming error, that is, “cone cuts”, which are frequently associated with the rectangular position-indicating device attached to the x-ray machine. Further, the use of the collimation plate of the present invention having a rectangular opening 16 reduces patient exposure to x-radiation by eliminating needless “retakes” of radiographs. The collimation plate 12 of the present invention is compatible with typical round (typically 2.75 in. or 7.0 cm diameter) indicating cylinder device that is typically standard on dental radiographic machines.

Another advantage of a device of the present invention pertains to the absorption of x-rays by the metal receptor holding member 28 which improves the quality of the acquired image on the film 54. The receptor holding member 28 is preferably constructed of a metal. The metal receptor holding member 28 will further reduce patient exposure to x-radiation by absorbing x-radiation that would ordinarily pass through the receptor or film 54. Also, the metal receptor holding member 28 reduces additional secondary or “scatter” radiation that causes degradation of the image.

As shown in FIGS. 1–16, the unitary design of the receptor positioning device 10 eliminates movement of multiple parts which could interfere with the exposure of the film 54. Further, the unitary design sets a fixed x-ray source-to-object distance and an object-to-film distance. Another advantage of the unitary design is the maintenance of uniform magnification and maximization of the sharpness of the acquired image. Another advantage of the receptor positioning device 10 is the preferred all metal design provides a rigid device which is also durable and lends itself to sterilizing using steam, heat or chemical methods. Moreover, the handles 18 which are part of the collimation plate 12 enables the patient to handle the device minimizing patient discomfort and malpositioning.

Another embodiment 310 of the present invention is shown in FIGS. 17–29, which depict a collimation and shielding device substantially as previously described, but removably securable to an otherwise conventional aiming ring of a typical film holding instrument. The aiming ring is used for assisting in positioning the x-ray machine. Referring to FIGS. 17–21, the collimation/shield device 310 includes a substantially flat, circular collimation plate 312 having opposite surface areas 314, 350 which define a substantially central rectangular opening 316 of width 421 and height 422. The preferred collimation plate 312 again includes two elongated handles 318, 319, but at substantially right angles from one another extending outward on two adjacent sides thereof. Alternatively, the collimation/shield may have a pair of handles 318, 318 a extending outward substantially opposite of one another, as shown in FIGS. 1 and 2 of the previous embodiment. The handles may extend along a radius of the collimation plate 312, as with handles 318, 318 a and 319, or the handles may be offset or otherwise non-radial, as with handles 318′, 319′. The collimation/shield device preferably has at least one handle, but may have more than the two shown in the drawing figures.

To enable facile securing to the ring of a receptor positioning device, the collimation/shield instrument further includes an attachment member 320 having raised corner tabs and a pair of attachment clips for attaching the shield to a typical film holder aiming ring. The attachment member 320 is centrally positioned and may be connected at a flat portion 322 of its front surface or edge to the front or rear surface of the collimator plate, preferably, by welding or other rigid connection, so that the attachment member is fixedly coupled to the collimation shield. Instead of being formed separately, the attachment member 320 may be formed in one piece with the collimation/shield device 310. As described previously, the thickness of the collimation/shield (along with the attachment member) is at least 0.075 in. (1.9 mm) thickness, more preferably 0.080 (2.0 mm) or 0.100 in. (2.5 mm) or more to block excess radiation.

The surface area of the attachment member preferably defines a substantially central rectangular opening 338 of the same dimension as rectangular opening 316 of the collimation/shield device. The opening in the collimation/shield device is oriented similarly and corresponds dimensionally to the film or other receptor to be used in the film holding instrument. In the preferred embodiment shown in FIGS. 17–19, the horizontal dimension 421 is about 1.500 in. (3.8 cm) and the vertical dimension 371 of the opening is about 1.200 in. (3.05 cm) for use with the adult size horizontal and vertical bitewing and periapical examination of patients with normal anatomy and dentitions. Other sizes may be made for small adults, children and other uses. For example, a vertical dimension of about 1.000 in. (2.54 cm) and a horizontal dimension of about 1.500 in. (3.8 cm) is for use for horizontal bitewing and periapical examination of small children (2–8 years) and very small adults or adults with a limited ability to open their mouths, and a vertical dimension of about 1.063 in. (2.7 cm) and horizontal dimension of about 1.688 in. (4.29 cm) is useful for observing compromised dentitions (with large restorations and height of alveolar crest bone decreased by marginal periodontal disease) that would not be visualized in horizontal bitewing and large adult periapical images.

Referring in particular to FIGS. 17, 19–24 and 27, the attachment member 320 has a pair of opposing spring clips 330 designed and adapted to receive and grasp the typical aiming ring 372 on a prior art intraoral film holder 370 (FIGS. 25, 28 and 29). The preferred overall height 400 between the attachment member 320 and the formed clips 330 is about 0.375 in. (9.5 mm). The over all length 340 of the attachment member 20 with the clips bent is preferably about 2.406 in. (6.1 cm) and the length 320 between the bent clips 330 is preferably about 2.125 in. (5.4 cm), as shown in FIGS. 23 and 24. The preferred length of the clip base 450 is about 0.0625 in. (1.6 mm), the preferred angle of bend 421 between the clip base and the clip upright portion is about 112° , the preferred height 410 between the clip base and shoulder is about 0.125 in. (3.2 mm), and the preferred projection 441 of the shoulder is about 0.0625 in. (1.6 mm). Clips 330 engage the inner periphery of aiming ring 372 (FIG. 25) in order to removably secure the attachment member 320 and collimation plate 312 to the ring. This is done by flexing or bending the clips inward, toward each other in direction 415 (FIG. 27), and inserting them into the aiming ring opening. When released, the clips are urged outward by their spring action and secure the collimation/shield device 310 in place over aiming ring 372.

The preferred attachment member 320 also includes four raised corners tabs 326 to align with the index indentations 373 of film holding aiming ring 372 (FIGS. 25 and 26). The pair of recesses in each index indentation 373 permits different orientation of the collimation/shield device. The raised corner tabs are disposed at the corners of the substantially rectangular attachment member 320, and have dimensions 370 and 371, as shown in FIG. 19. The preferred dimension 371 is about 1.1875 in. (3.0 cm) and the preferred dimension 370 is about 1.563 in. (3.9 cm). In this embodiment, the raised corner tabs 326 have a edge width 480 of about 0.185 in. (4.8 mm) and have a rise dimension 429 of about 0.0625 in. (1.6 mm). The corner tabs are each delineated by a notch 324 of a preferred dimension 425 of about 0.25 in. (6.35 mm) and an angle of 45° relative to each side of the attachment member. When collimation/shield device 310 is clipped to the aiming ring, the corner tabs fit into the index indentations 373 of aiming ring 372, as shown in FIG. 26, to locate and prevent rotation of the collimation/shield device relative to the aiming ring. The indentations also permit vertical or horizontal orientation of the substantially rectangular central opening by rotating the shield device 90° prior to attaching to the aiming ring of a typical film holding instrument, thereby providing positive orientation in two positions.

Referring to FIGS. 28 and 29, in operation and use, the collimation/shield device 310 is preferably first clipped to the aiming ring 372. Then the plastic biting portion 376, secured to the film holding instrument 370 by connector 374, is inserted into the patient's mouth 65. The patient's teeth 60 a to be x-rayed rest on and bite on the biting portion. The receptor holding member 378 of the biting portion 376 is positioned behind the teeth 60 a to be exposed and the aiming ring 372 with the attached shield device 310 is positioned adjacent to the patient's mouth 65 and teeth 60 a. The x-ray machine 63 is positioned to take an x-ray in front of the shield device 10 and expose the x-ray film 354. Preferably the collimation/shield device 310 is constructed of metal and rigidly and fixedly fashioned for precise attachment to the typical aiming ring. The patient or radiographer grasps the handles 318, 319 to position and maintain the film holding instrument in the optimal aimed position with better comfort

As described previously, and as shown in FIGS. 28 and 29, collimation plate 312 is adapted to axially align the x-ray machine's position indicating cylinder device 62 with the receptor 354 shown by the x-ray center line the 63. It does this in two ways. First, the x-ray machine is easily centered because preferably the two devices 312, 62 have substantially the same diameter. Axial offset would be apparent by extension of the outer rim of the x-ray machine position indicating cylinder device 62. Second, substantially full, flat contact of the collimation plate 312 with the x-ray machine's position indicating cylinder device 62, as shown in FIGS. 28 and 29, would assure optimal alignment of the x-ray receptor with the x-ray beam.

The rigid and fixed construction of the shield device 310 provides the most accurate film exposure because there is minimal opportunity for unwanted movement after positioning the device. The metal collimation/shield device having the rectangular opening reduces patient exposure by absorbing approximately 50% of the primary beam x-radiation for most commonly prescribed dental intraoral radiographs, which are the bitewing and periapical views. As with the previous embodiments, the metal collimation/shield device of FIGS. 17–29 reduces aiming error, or cone cuts, and eliminates needless retakes of radiographs for typical prior art film holding instruments.

The collimation/shield device 310 of the present invention is compatible with a round indicating cylinder device 62 of 2.75 in. (7.0 cm) diameter that is typically standard on dental radiographic machines and with the round aiming ring 372 of 2.75 in. (7.0 cm) diameter that is a component of a typical intraoral film holder 70. The unitary design of the shield device 10 permits precise attachment to the typical aiming ring 372, thus, preventing additional movement that could interfere with the exposure of the film 54. Another advantage of the collimation/shield device is that, prior to attaching, the orientation of the central opening 316 of the shield can be rotated 90° relative to the aiming ring and selected film holding member of typical receptor positioning instruments, thus, permitting vertical or horizontal orientation. Another advantage of the collimation/shield device 310 is the preferred all metal design provides a rigid device which is also durable and lends itself to sterilization using steam, heat or chemical methods. Moreover, the handles 318, 319 which are part of the collimation/shield device 310 enable the patient to handle the device minimizing patient discomfort and malpositioning.

While the present invention has been particularly described, in conjunction with a specific preferred embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. It is therefore contemplated that the appended claims will embrace any such alternatives, modifications and variations as falling within the true scope and spirit of the present invention. 

1. A receptor positioning device for taking dental bitewing radiographs of a patient's teeth, which comprises: a receptor holding member adapted to receive a receptor for exposing x-radiation from the x-ray machine; an aiming ring for assisting in positioning the x-ray machine; an arm secured between the aiming ring and the receptor holding member, the arm including a biting surface for engaging the patient's teeth to secure the device in the patient's mouth; and a collimation plate having clips removably securing the plate to the aiming ring, a substantially flat surface for aligning with an x-ray machine, an opening in the plate surface for passage of radiation from the x-ray machine to expose a receptor in the receptor holding member, and a handle extending away from the plate for positioning the device, the collimation plate being constructed of metal having a thickness of at least 0.075 in. to reduce the passage of radiation from the x-ray machine to the patient except at the plate opening.
 2. The device of claim 1 including a pair of handles extending from the collimation plate at approximately a right angle to each other.
 3. The device of claim 1 wherein the device further includes a receptor for exposing x-radiation from the x-ray machine and wherein the opening in the collimation plate corresponds in dimension to the receptor to reduce overexposure of the patient.
 4. The device of claim 1 wherein the aiming ring includes notches and the collimation plate further includes tabs for locating the plate relative to the aiming ring notches.
 5. A method for taking dental bitewing radiographs of a patient's teeth comprising: providing a receptor positioning device including a receptor holding member adapted to receive a receptor for exposing x-radiation from the x-ray machine; an aiming ring for assisting in positioning the x-ray machine; an arm secured between the aiming ring and the receptor holding member, the arm including a biting surface for engaging the patient's teeth to secure the device in the patient's mouth; and a collimation plate having clips removably securing the plate to the aiming ring, a substantially flat surface, an opening in the plate surface, and a handle extending away from the plate, the collimation plate being constructed of metal having a thickness of at least 0.075 in.; providing a receptor on the receptor holding member; positioning the receptor holding member in the patient's mouth and the patient's teeth on the biting surface to secure the device in the patient's mouth; adjusting the position of receptor positioning device by grasping the handle extending from the collimation plate; aligning an x-ray machine with the substantially flat surface of the collimation plate; and passing radiation from the x-ray machine through the opening of the collimation plate while substantially blocking passage of radiation through the collimation plate thickness to expose the receptor.
 6. The method of claim 5 wherein the device includes a pair of handles extending from the collimation plate at approximately a right angle to each other, and including grasping the handles to adjust the position of receptor positioning device.
 7. The method of claim 5 wherein the opening in the collimation plate corresponds in dimension to the receptor to reduce overexposure of the patient to the radiation.
 8. The method of claim 5 wherein the aiming ring is secured to the arm at a position distal from the receptor holding member, and further including securing the collimation plate to the aiming ring with the clips.
 9. The method of claim 5 further including bending the clips to secure the collimation plate to the aiming ring.
 10. The method of claim 5 wherein the aiming ring includes notches and the collimation plate further includes tabs for locating the plate relative to the aiming ring, and further including inserting the collimation plate tabs into the aiming ring notches.
 11. The method of claim 5 wherein the aiming ring includes notches and the collimation plate includes tabs for locating the plate relative to the aiming ring, and further including bending the clips to secure the collimation plate to the aiming ring and inserting the collimation plate tabs into the aiming ring notches.
 12. A method for taking dental bitewing radiographs of a patient's teeth comprising: providing a receptor positioning device including a receptor holding member adapted to receive a receptor for exposing x-radiation from the x-ray machine; and an aiming ring for assisting in positioning the x-ray machine; an arm secured between the aiming ring and the receptor holding member, the arm including a biting surface for engaging the patient's teeth to secure the device in the patient's mouth; providing a collimation plate having clips for removably securing the plate to the aiming ring, a substantially flat surface, an opening in the plate surface, and a handle extending away from the plate, the collimation plate being constructed of metal having a thickness of at least 0.075 in.; providing a receptor on the receptor holding member, the receptor corresponding in dimension to the collimation plate opening; securing the collimation plate to the aiming ring with the clips; positioning the receptor holding member in the patient's mouth and the patient's teeth on the biting surface to secure the device in the patient's mouth; adjusting the position of receptor positioning device by grasping the handle extending from the collimation plate; aligning an x-ray machine with the substantially flat surface of the collimation plate; and passing radiation from the x-ray machine through the opening of the collimation plate while substantially blocking passage of radiation through the collimation plate thickness to expose the receptor and to reduce overexposure of the patient to the radiation.
 13. The method of claim 12 wherein the device includes a pair of handles extending from the collimation plate at approximately a right angle to each other, and including grasping the handles to adjust the position of receptor positioning device.
 14. The method of claim 12 wherein the aiming ring is secured to the arm at a position distal from the receptor holding member.
 15. The method of claim 12 further including bending the clips to secure the collimation plate to the aiming ring.
 16. The method of claim 12 wherein the aiming ring includes notches and the collimation plate further includes tabs for locating the plate relative to the aiming ring, and further including inserting the collimation plate tabs into the aiming ring notches.
 17. The method of claim 12 wherein the aiming ring includes notches and the collimation plate includes tabs for locating the plate relative to the aiming ring, and further including bending the clips to secure the collimation plate to the aiming ring and inserting the collimation plate tabs into the aiming ring notches. 